Exposure to per- and polyfluoroalkyl substances (PFAS) through drinking water in Barcelona metropolitan area

Abstract

BACKGROUND AND AIM: Per- and polyfluoroalkyl substances (PFAS) are a group of water-soluble chemicals of concern due to their persistence, widespread human exposure and associated adverse health outcomes across all life stages. Drinking water is one of the main routes of human exposure to PFAS. METHODS: We assessed 38 PFAS in 64 drinking water samples sourced from tap water (N=42, one per postal code), bottled (N=11), activated carbon (N=6) and reverse osmosis (N=5) filtered tap water in Barcelona, Spain. Liquid chromatography coupled tandem mass spectrometry was used to determine PFAS. Physico-chemical properties including residual chlorine, total organic carbon and conductivity were also measured. Water consumption habits of study participants (N=39) were collected through online questionnaires. RESULTS:The most abundant PFAS in unfiltered tap water were perfluoropentanoic acid (PFPeA) [3 ng/L (2.0-5.0)] -among 64% samples above the limit of quantification (LOQ)-, perfluorohexanoic acid (PFHxA) [14 ng/L (10-18)] -31%-, perfluoroheptanoic acid (PFHpA) [3 ng/L (2.25-4)] -52%-, perfluorooctanoic acid (PFOA) [11 ng/L (10-12)] -12%-, perfluorobutane sulfonic acid (PFBS) [9 ng/L (6.5-14.5)] -64%-, and perfluorooctane sulfonate (PFOS) [12.5 ng/L (10-14)] -52%-, with corresponding median (interquartile range, IQR). The median concentration of total PFAS was 29 ng/L (IQR=24-51), among 79% of tap water samples with PFAS LOQ. Individual PFAS displayed a range of positive correlations (Spearman, two-tailed) between r=0.36 (p=0.02) and r=0.67, (p0.001). Conductivity showed a geographical pattern linked to the tap water source, and a positive correlation (r=0.75, p0.001) with total PFAS. Reverse osmosis removed PFAS from tap water, while activated carbon filters did not. PFAS were not detected in bottled water. The mean consumption of water at home was 1.4L/day, and 0.8L/day outside of home. The main source of water was tap (43%) at home, and bottled or filtered (37.5% each) outside. CONCLUSIONS:Concentrations were below the EU Drinking Water Directive 2020/2184 PFAS Total parametric value (100 ng/L). KEYWORDS: PFAS, Exposure assessment, Chemical exposures, Water quality